Confined Space Entry - Strategies & Effective Practices to Manage and Mitigate Hazards | AIChE

Confined Space Entry - Strategies & Effective Practices to Manage and Mitigate Hazards

Last updated September 27, 2018 | Element: Strategies & Effective Practices to Manage and Mitigate Hazards

Effective Practices to Manage and Mitigate Hazards


Reduce risk by minimizing confined space entry work on vessels connected to equipment still in operation

  • Consider deferring confined space entry to a future turnaround or outage when inventories of hazardous materials are at a minimum or eliminated.

Properly isolate line or equipment to be worked on

  • Use blinds or physical disconnects.
  • Do not use valves as isolation devices.
  • Lock-out/tag-out should be completed, including moving parts (i.e. agitators) before confined space entry permit is issued.

Clean the equipment before opening

  • Develop procedures to clean or flush the equipment to minimize the amount of hazardous materials present.

Verify that the equipment is drained and clean before proceeding with confined space entry task

  • Develop procedures to ensure that the equipment is emptied, purged, flushed, drained, vented, isolated and locked/tagged as applicable to confirm the system is free from recognized hazards.
  • Assure that drains are not plugged giving a false indication that the equipment is empty.

Assure that personnel are not exposed to hazardous materials while draining the equipment

  • Develop procedures to empty, purge, flush, drain, vent, and properly isolate lines and equipment.
  • Verify that de-pressurization of lines or equipment and absence of material has been accomplished by opening vents and drains or by other means deemed appropriate.
  • Include proper disposal of hazardous materials in draining procedures.

Treat initial line/equipment opening to isolate equipment for confined space entry as if hazardous material is present

  • Require personnel performing line breaking to wear proper PPE for the hazardous material that is normally in the line.
  • PPE should remain in place until personnel verifies that the line is empty and clean.
  • Loosen the flange bolts away from you first to minimize exposure in case of a release.

Identify location of each isolation point for confined space entry

  • Identify the location of needed blinds or disconnects by marking on the pipe.
  • Positively identify location of each line opening at the time of on-site inspection.
  • During on-site inspection verify that person performing the work or accepting the permit knows the location of the line opening.
  • Ensure a blinding list is adequate and updated (consider marking the P&IDs as well).

Properly lock-out equipment

  • Assure that any rotating equipment such as agitators are properly de-energized and locked out.

Eliminate exposure from radiation devices

  • Shutter on radiation devices must be closed and locked.
  • Verify absence of radiation hazard by using proper equipment and properly trained industrial hygiene personnel.

Eliminate possibility of engulfment if the confined space is a trench or a pit

  • Slope side s of the excavation.
  • Properly shored up sides to prevent collapse.
  • Use trench shields or trench boxes.

Identify access issue or congestion in the area and develop a rescue plan with proper equipment in place

  • Assure adequate access to personnel in the confined space.
  • Identify rescue equipment and develop rescue plan.
  • Assure rescue equipment is available and set up per rescue plan.

Properly test atmosphere in the confined space

  • Assure monitors used for atmosphere testing are properly calibrated.
  • Test atmosphere at several locations and heights in the confined space.
  • Test confined space for toxics, flammables and oxygen deficiency.

If hot work is to be performed in the confined space, follow proper procedure

  • Obtain hot work permit.
  • Assure gas supply bottles are not taken into confined space.
  • Make sure electrical equipment is connected through a ground fault interrupter.

If pneumatic tools are used assure that proper procedures are followed

  • Use only air (not nitrogen) to operate pneumatic tools.
  • Make sure electrical equipment is connected through a ground fault interrupter.

Provide proper ventilation and lighting

  • Use positive ventilation on confined space such as blowers, fans or venturi.
  • If flammables are present, use low voltage explosion proof lights.

Recognize changes in process conditions

  • Confined space entry that last over several hours or days needs to be secured to assure no authorized entry occurs.
  • Atmosphere is the confined space should be checked before any re-entry to the space.

Ensure resources to adequately assess safe work activities

  • Pressure on authorizing personnel to get permits issued can compromise the safety process through the adoption of a “seems OK to be” process. 
  • Assure that there are enough resources to properly inspection the line opening site and positively identify the location of the line opening before permit is issues.

Create safe environment

  • Require proper fall protection during the confined space entry.
  • Identify location of the nearest safety shower and eyewash to be used in case of an emergency.

Continuous monitoring of the environment; stopping work if hazardous material is detected in the line

  • Confined space entry should be stopped if presence of hazardous material is detected.
  • Hazard evaluation should be completed to determine how the work should proceed or if it should be postponed.

Communication is essential between the control room, the Operating personnel and the people conducting the work

  • Communication with the control room at all times is essential. 
  • If an emergency alarm is sounded, all confined space entries must cease immediately. 
  • Area should be re-inspected and confined space entry permit re-issued after emergency is resolved.